Not excited about my D800

Started Jun 4, 2012 | Discussions thread
Brandon birder Veteran Member • Posts: 4,151
Re: Grow into it

Antony John wrote:

Brandon birder wrote:

Antony John wrote:

Sorry to inteject but how does one keep detail when downsampling must, by consequence, decrease it by merging adjacent pixels?

I've heard this before but trying to get a handle on how this can work.

You don't keep all the detail but the downsampling algorithms use the extra information to help decide what should be kept, deleted or merged. The better the original information, the better the down sampled image. An image from a 12mpx sensor will contain less detail than a 36mpx sensor image down sampled to 12 mpx as a result.

In addition downsampling decreases noise and increases the appearance of sharpness.

Thanks for the answer but I'd like to see definitive proof of this and whilst no doubt the averaged noise will be less I'd rather not have to rely on algorithmic interpolation.

Some 'real life' comparisons on sharpness of the same scene under the same conditions would be proof of the hypothesis and algorithmic accuracy. If anyone has a reference site where this has been done it would be appreciated.
Cheers

That's ok Anthony. I don't have any proof though I'm sure someone has (maybe an information theorist) but we do accept this notion in another common area of our lives that is audio CD's. The musical masters carry information at a much higher frequency (cf resolution) than the final product. I'm sure this is done for a reason otherwise they would sample at the same rate that they want to output. Just a thought.
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Cheers, BB

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